We propose to investigate the detailed molecular interactions of adriamycin, a potent antitumor antibiotic, with DNA. A series of experiments is proposed to study the effect of adriamycin on the physical integrity of DNA in rat heart cells grown in culture. An effort will be made to define conditions which lead either to reduced DNA damage or to enhanced DNA repair. Laser Raman scattering spectra for bound drug -DNA complexes in vitro should provide data enabling identification of intercalative and ionic modes of drug - DNA binding and specific groups on both the drug and DNA which are involved in the interaction. The objective of this work is an attempt to gain insight into the molecular basis for cardiotoxicity accompanying treatment of malignancies in humans.